The present invention relates to improvements in machines and/or apparatus wherein one or more rotary members are installed in stationary or mobile supports and carry one, two or more fluid-operated aggregates in the form of couplings, clutches, brakes, clamping devices or the like which receive a pressurized control fluid (e.g., oil) by way of a distributor valve system including axially movable valve members in the form of spools having axially spaced plungers or lands. Examples of machines which employ a plurality of rotary members in the form of work supporting spindles are multiple-spindle automatic machine tools wherein the spindles are rotatable in a rotary drum-shaped spindle carrier which is indexible between a plurality of positions to thereby move the front ends of successive spindles into optimum positions with respect to material removing tools at a plurality of working stations. As a rule, each spindle is mounted in at least two antifriction bearings of the spindle carrier and each spindle can carry three or more aggregates including a brake which can rapidly arrest the respective spindle, a clamping device which can engage a workpiece at the front end of the respective spindle, and one or more clutches which can couple the respective spindle to gears or analagous torque transmitting elements to thereby rotate the spindle at a selected speed.
Each aggregate may comprise a single-acting or a double-acting cylinder whose chamber or chambers receive pressurized control fluid or discharge control fluid in selected axial positions of the associated valve member. Fluid-operated (especially hydraulically operated) aggregates are becoming increasingly popular in control systems of machine tools, multi-speed transmissions or the like because their development has reached a highly advanced stage so that a fluid-operated clutch or brake is normally preferred over a mechanically or electrically operated clutch or brake. As a rule, a fluid-operated clutch or brake can transmit or take up a torque exceeding up to four times that torque which is transmitted or taken up by an equally small or even larger electrically or mechanically operated clutch or brake. Moreover, a fluid-operated brake or clutch can stand substantially greater thermal stresses than a mechanically or electrically operated brake or clutch.
A serious problem which remains to be solved in machines employing spindles, shafts or analogous rotary members supporting one or more fluid-operated aggregates which receive pressurized control fluid by way of distributor valve is that of supplying the control fluid to selected aggregates in a space- and material-saving manner. The situation is aggravated in multiple-spindle machine tools of the type known as bar machines wherein elongated bar stock is fed lengthwise through the axial passages of hollow work supporting spindles, and also in turning machines wherein a shaft in a multi-speed transmission or a work supporting spindle must carry a large number of brakes and/or clutches. In presently known machines, the fluid-operated aggregates on the rotary members receive control fluid which flows radially inwardly into the chamber of chambers of stationary single-acting or double-acting cylinders of the respective aggregates. Such proposal has met with little success due to generation of excessive heat, especially when the rotary member or members are driven at a high speed. Moreover, discrete groups of fluid supplying and evacuating conduits must be provided for each aggregate, and the flow of fluid in each group of conduits must be regulated by a discrete control valve which necessitates complex and expensive actuating means for moving the valve member relative to the valve body.